201001TimesinπtπtZeroandﬁrstorderholdt0t1t2t3t4t5t6Timet0t1t2t3t4t5t6TimePredictiveﬁrstorderhold•UseforwarddifferenceinsteadofbackwarddifferenceuDkhτEuDkhEτhDuDkhhEuDkhEE•Usemodelofthecontroller.t0t1t2t3t4t5t6TimeSinusoidalsignalwithh1andh0.5051001Zero order holdh=1051001First order hold051001Predictive holdTime051001Zero order holdh=0.5051001First order hold051001Predictive holdTimec&Dept.ofAutomaticControl,Lund4Discretetimeapproximationofcontinuoustimecontroller—FrequencydomainImplementingacontrollerusingacomputerAlgorithmClock